The present invention relates to a mutual authentication method for use among a recording apparatus, reproducing apparatus, and recording medium, using a contents management technique that protects copyrights by limiting the number of copied contents, and a recording apparatus, reproducing apparatus, and recording medium using the method.
Conventionally, contents (literary works and the like) have undergone copy management. More specifically, by managing copy generations or the number of copies, copyright protection and use are balanced.
On the other hand, the concept “move” has appeared as an alternative to copy management. “Copy” does not erase original data, but “move” transfers data to another location (recording medium) and erases original data. As a result, a protection technique against “move” has appeared. Such technique has emerged due to digitalization of contents and prevalence of networks and the like.
However, in recent years, since copies faithful to an original can be formed via the network or the like, it becomes difficult for the conventional technique to reliably protect copyrights. Particularly, it is hard to reliably protect copyrights against unlimited moves from medium to medium, e.g., profit-making distribution (by means of move) of data.